1. Field of the Invention
The invention relates to the technical field of image processing and, more particularly, to a method and system of eliminating color noises caused by an interpolation.
2. Description of Related Art
A color image processing system essentially includes an image capturing unit, an image restoring and processing unit, an image display and an image compressor. The image capturing unit includes an image sensor, which is a sensitive device consisting of multiple photodiodes arranged in a 2D array and cooperates with a color filter array to thereby obtain a single color value for each pixel. The image restoring and processing unit applies an interpolation to each pixel for restoring red (R) color, blue (B) color and green (G) color of the pixel. The interpolation and restoration may cause obvious color spots at a boundary between white pixel and black pixel. In addition, when the image sensor is capturing source image data, the captured image data is likely to include noises, and the process of interpolation and restoration can also cause the noises to diffuse around the adjacent pixels.
A known median filter can be provided to reserve the edge information while noises are eliminated, so that an image does not appear any blur effect. Accordingly, the U.S. Pat. No. 5,778,106 uses a median filter to eliminate color noises of R-G and B-G However, the color noises caused in restoring by the interpolation appear in clusters. Therefore, a 2D median filter with a small range (such as 3×3) cannot effectively eliminate the color noises. A 2D median filter with a larger range (such as 7×7 or 9×9) can filter out the color noises but significantly increases the cost.
Therefore, it is desirable to provide an improved method and system to mitigate and/or obviate the aforementioned problems.